path: root/include/acpi/acpixf.h
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authorLv Zheng <lv.zheng@intel.com>2014-05-31 08:14:44 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-06-01 00:18:52 +0200
commit47d68c7f688c01557cb67dd80eb540e88d7913b6 (patch)
treebc1415fd1b1ead6a1fe0818458f890ebed2ec4e1 /include/acpi/acpixf.h
parent2947c1d5f72b77078aeb3df05d4298274234534d (diff)
ACPICA: Tables: Add mechanism to control early table checksum verification.
It is reported that Linux x86 kernel cannot map large tables. The following large SSDT table on such platform fails to pass checksum verification and cannot be installed: ACPI: SSDT 0x00000000B9638018 07A0C4 (v02 INTEL S2600CP 00004000 INTL 20100331) It sounds strange that in the 64-bit virtual memory address space, we cannot map a single ACPI table to do checksum verification. The root cause is: 1. ACPICA doesn't split IO memory mapping and table mapping; 2. Linux x86 OSL implements acpi_os_map_memory() using a size limited fix-map mechanism during early boot stage, which is more suitable for only IO mappings. ACPICA originally only mapped table header for signature validation, and this header mapping is required by OSL override mechanism. There was no checksum verification because we could not map the whole table using this OSL. While the following ACPICA commit enforces checksum verification by mapping the whole table during Linux boot stage and it finally triggers this issue on some platforms: Commit: 86dfc6f339886559d80ee0d4bd20fe5ee90450f0 Subject: ACPICA: Tables: Fix table checksums verification before installation. Before doing further cleanups for the OSL table mapping and override implementation, this patch introduces an option for such OSPMs to temporarily discard the checksum verification feature. It then can be re-enabled easily when the ACPICA and the underlying OSL is ready. This patch also deletes a comment around the limitation of mappings because it is not correct. The limitation is not how many times we can map in the early stage, but the OSL mapping facility may not be suitable for mapping the ACPI tables and thus may complain us the size limitation. The acpi_tb_verify_table() is renamed to acpi_tb_verify_temp_table() due to the work around added, it now only applies to the table descriptor that hasn't been installed and cannot be used in other cases. Lv Zheng. Tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/acpi/acpixf.h')
1 files changed, 9 insertions, 0 deletions
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index b5f7132f431f..35b525c19711 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -162,6 +162,15 @@ ACPI_INIT_GLOBAL(u8, acpi_gbl_create_osi_method, TRUE);
ACPI_INIT_GLOBAL(u8, acpi_gbl_use_default_register_widths, TRUE);
+ * Whether or not to verify the table checksum before installation. Set
+ * this to TRUE to verify the table checksum before install it to the table
+ * manager. Note that enabling this option causes errors to happen in some
+ * OSPMs during early initialization stages. Default behavior is to do such
+ * verification.
+ */
+ACPI_INIT_GLOBAL(u8, acpi_gbl_verify_table_checksum, TRUE);
* Optionally enable output from the AML Debug Object.
ACPI_INIT_GLOBAL(u8, acpi_gbl_enable_aml_debug_object, FALSE);

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